Catheter mounted automatic vessel occlusion and fluid dispersion devices

ABSTRACT

Catheter or guidewire mounted automatic vessel occlusion and fluid dispersion devices that expand to occlude or partially occlude a vessel when a fluid is flowing in the catheter or guidewire, and that automatically collapse when fluid flow is stopped. Each occlusion device has an elastic skeleton covered with a flexible cover coupled thereto and may have a hole(s) or openings in its distal or proximal end thereof to allow controlled flow through the desired end of the occlusion device. The fluid may be a flush fluid for enabling or improving the performance of imaging devices and image enhancing fluids, of treatment fluids for localized treatment of a vessel or tissues in communication with the vessel and/or of the transmission of energy to the vessel wall and adjacent tissues. Various embodiments are disclosed.

This application is a continuation of U.S. patent application Ser. No.11/295,419, filed on Dec. 6, 2005 now U.S. Pat. No. 8,197,411.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to the field of occlusion/infusion andocclusion/imaging devices and systems.

2. Prior Art

It is increasingly important that a physician or surgeon deliveringsubstances, such as a treatment agent or drug or an image-enhancingagent, is able to efficiently and accurately locate and/or effectivelydeliver the substance to the desired target tissue. This is particularlytrue when the concentration of the substance required at the target sitecannot be safely or effectively achieved by introduction of thesubstance to a location remote from the target site or the flow of bloodwashes away or dilutes the substance too rapidly at the target site.Moreover, the physician may only want to treat the diseased portion of avessel, organ or tissue and avoid treating the healthy portions.

For example, to achieve localized treatment of tissue, such as tissue ina heart, physicians and surgeons can use catheters and/or guidewires,which may include a balloon(s) and an inflation lumen(s) for use as anocclusive device. Specifically, cardiovascular guide catheters aregenerally percutaneous devices used to advance through a vasculature ofa patient to a region of interest and are devices through which anothercatheter or device may be inserted. Also, guide catheters commonly haveimaging agents injected through their lumen to aid in their positioningand to aid in the visualization of a vascular region of interest. Guidecatheters are generally inserted into a proximal percutaneous vascularaccess site via the inner diameter of a shorter catheter-like device, anintroducer. Delivery catheters are generally catheters used to deliver atreatment agent(s) and/or diagnostic device(s) to a region of interestin a vasculature of a patient and typically may be inserted throughanother catheter (e.g., a guide catheter) while engaged with aguidewire. Delivery catheters may be provided with a lumen(s) and aport(s) to allow the delivery of fluids into the vasculature at thedistal end of the delivery catheter and/or at a port(s) along the lengthof the catheter. Guidewires are generally devices that engage a guidecatheter or delivery catheter and are used to guide them through avasculature of a patient to a region of interest and are typicallyinserted into the vasculature through another catheter (e.g., the guidecatheter, the delivery catheter) or while engaged with another catheter.Typically, the guidewire is advanced into and sub-selects the desireddistal vasculature region of interest and then the catheter is advancedover the guidewire to a more distal position. Moreover, balloons may beattached to a delivery catheter, guidewire or guide catheter and aninflation lumen provided to allow balloon inflation and deflation toocclude at will a region of interest in a vasculature.

Also, current OCT (optical coherence tomography) imaging systems are notable to image much more than about 2 mm (typically 1.2 to 1.7 mm) intoblood or tissue. Because vessels for which imaging is desired aregenerally 2 mm in diameter or greater and the imaging device may be incontact with a vessel wall, it is not practical to expect to image thewall of these vessels over their full 360 degree circumference to anyvessel wall depth without clearing the blood from the field of view,eliminating the blood's properties impacting imaging depth and/orcontrolling the catheter's position relative to the vessel wall.Clearing may be accomplished by replacing the blood with a saline orother water based solution (flushing), such as by injecting the solutiondown the guide catheter.

The frequency of light used in OCT imaging systems is such that itswavelength is short enough for it to interact with individual red bloodcells. Use of longer wavelengths to avoid the red blood cell interactionresults in a loss of the desired image axial (depth) resolution forvulnerable plaque (VP) detection. The red blood cells have a slightlyhigher index of refraction than the plasma in which they are suspended.In addition, the red blood cells are shaped like concave lenses, so theOCT light may be re-directed and refocused (diverged) by each red cellit passes through, both to and from the tissue/vessel wall to be imaged.In addition, there are some comparatively minor light energy losses dueto absorption and path length changes due to scattering (reflection) bythe red cells.

IVUS (intravascular ultrasound) may also be used to image VP's at thedesired resolutions, if a high enough ultrasonic frequency is used. Inhigh frequency IVUS systems, the red blood cells are imaged andblock/attenuate the ultrasound, degrading the imaging depth. Therefore,such systems will also require a flush for reasons similar to theproblems of OCT.

In photodynamic therapy systems, the frequency of the light may be evenhigher than that used in OCT systems. Thus, to control the amount oflight energy that reaches the vessel wall within acceptable limits andto limit the possible damage to the blood cells, flushing is likely tobe required.

Flushing of coronary arteries to remove blood from the field of view ofthe OCT device, very high frequency IVUS device or path of aphotodynamic therapy beam is normally accomplished by injecting salineinto the vessel to be imaged, either through the guiding catheter or acatheter/sheath that surrounds/incorporates the device. However, asimple flush has quite a few drawbacks and problems:

1. When one effectively flushes, the blood is replaced/extremely dilutedwith another fluid, usually a saline or other isotonic biocompatiblewater-based solution, which has little oxygen captured in it. Thus, thetime window for imaging is limited by the ischemia consequences of thesolution on the heart muscle. The more proximal the flush, the more ofthe heart muscle is affected. Since imaging is desired in patientsusually already suffering from ischemia or previous cardiac muscleischemic tissue damage, the safe/pain-free (the patient is usuallyconscious during a catheter based vascular procedure) flushing timeperiod is short.

2. Flow in coronary arteries is laminar and thus tends to flow instreamlines and not mix very rapidly with adjacent streamlines. Thus,injected solutions tend to flow in their own streamlines, leaving someareas of blood flow (some blood streamlines) not completelydisplaced/replaced or leaving eddies of blood at branch points or areasprotected/created by the device's/catheter's/sheath's presence.

3. Most water based flushing solutions have a viscosity that issignificantly less than that of blood. Thus, for the incoming flush tocreate enough pressure in the vessel/vessel path to exceed the bloodpressure and thus relatively completely displace the incoming blood, theflow rate of the flush must exceed the normal flow rate of the blood inthe vessel. In other words, the resistance to flow in the vessel islower for the flush than for the blood. So as the flush replaces theflowing blood at the arteriole level, a greater and greater flow rate ofthe flush is required until a peak flow rate when the flush effectivelycompletely replaces the blood in the artery/arterioles downstream (theflow resistance of the capillaries/arteries is negligible compared tothat of the arterioles) and the arterioles are maximally opened inresponse to tissue ischemia. The volume of flush required can be quitehigh during extended flushing time periods.

4. In most injection configurations, the required high flush flow rateenters the vessel via a relatively small effective flow cross-section(catheter/sheath exit port(s)), thus the injection velocity is veryhigh. High velocity jets can be damaging to vessel walls. Additionally,the pressures and volumes required are not easily accomplished by manualinjections; an injection device is desirable. Injecting a more viscousfluid, like contrast, requires a lower flow rate, but the catheterinjection pressure is relatively unchanged due to its higher viscosity.A high viscosity injectate/flush also increases the time it takes towash out the flush (longer ischemic time after the flushing is stopped)and, of course, contrast is quite expensive relative to normal flushingsolutions.

Several methods to deal with these problems have been previouslysuggested/disclosed:

1. To solve the problems with light, oxygenated blood could be withdrawnfrom the patient and materials added to the blood to increase the indexof refraction of its plasma to that of the red blood cells and then useit as the flush, or this could be done systemically. This wouldeliminate/effectively minimize the lens effect and the reflectioneffects of the red blood cells. The remaining absorption effects wouldbe minor. Since the red blood cells are oxygenated, ischemia is not aproblem. It has been reported that contrast can be used to make thisindex of refraction change to the plasma. However, it is likely that itwould be very difficult or toxic to make this adjustment systemically.It is likely somewhat easier and faster to perform this with withdrawnblood, but this would require extra equipment/disposables and a timeconsuming index matching procedure, as well as issues involved withincreased blood exposure. The streamlines and injection problems wouldstill be a challenge and hemolysis could be an issue.

2. The imaging can be done very rapidly by decoupling the image datagathering from the image presentation. This limits the time required forflushing and minimizes ischemia. For any given imaging time, the longerthe vessel length to be imaged, the less the longitudinal resolution ofthe image data gathered during a controlled pullback over that length.However, calculations have shown that a significant length of vessel canbe imaged in a very short time and still retain longitudinal resolutionsthat will allow the reliable detection of VPs. The gathered images arerecorded and are accessed by the physician at a comprehensiblerate/physician controlled manner. If a VP is detected and an increasedlongitudinal resolution is desired, another pullback of a shorter lengthcan be performed between the pullback positions specified (positionsderived from the previous pullback's presentation data). This methodprovides a means to reduce the ischemic time and the volume of flushsolution required, but still requires high flush flow rates and doesn'tdeal with the problems of streamlines.

3. The distal end of a guide may be modified to deal with the problemsof streamlines with guide catheter infusions or flushing. High flowrates, especially since the guide is very proximal, are still required.The guide would have to be designed to be compatible with the imaging ortherapy device, and this might make it less compatible with otherdevices/catheters required to treat a VP or other medical condition.

4. One could image through a fluid filled balloon and eliminate the needfor a flush. However, this would still have the ischemia problem, woulddamage the vessel wall/the VP and likely distort the vessel so its imagewould be distorted. Imaging a long length of vessel would be verydifficult to design a balloon for, because the size of the vesselchanges along its length and the balloon inflation pressure would tendto straighten the vessel (damage/distortion). A large balloon could alsotake a long time to deflate. Also, one would not be able to imageeffectively through any air trapped in the balloon, due to index ofrefraction differences. If the balloon were made of a fluoropolymerand/or very thin, then the balloon material wouldn't interferesignificantly with the OCT light. Water/water-solution filledperfluorocarbon catheter lumens will not interfere significantly withOCT light.

5. Flushing just proximal to the length of vessel to be imaged will helplimit the flush flow rate required, at least where the imaging positionis distal in the vessel. This implies that the imaging be done in acatheter or a sheath, and that the imaging device engage a sheath orcatheter or a flushing sheath/catheter be inserted along with theimaging device. Since the rotating OCT imaging assembly (imaging core)can be made so small, on the order of 0.004″ diameter, it can beincorporated into a flushing sheath/catheter/other catheter with littlesize increase. Or, if the imaging device is a guidewire, use a flushingsheath to retain guidewire position after an imaging pullback. Such asystem could still be as small or smaller than current IVUS catheters,which can access the vessels of interest.

Also known in the prior art are embolic protection devices, and systemsfor enabling the insertion and removal of embolic protection devices,for capturing and retaining embolic debris, which may be created duringthe performance of a therapeutic interventional procedure in a stenosedor occluded region of a blood vessel. Devices and systems of this kindinclude devices and systems that have a strut assembly or cage,generally self expanding, with a filter element thereover. Devices andsystems of this type are disclosed in Published U.S. Patent ApplicationsNos. 2003/0120303, 2003/0144685, 2003/0212361, 2004/0006361 and2004/0098032, and are sold under the trademark ACCUNET.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an illustration of an occlusion/flush dispersion device of oneembodiment of the present invention shown in the retracted condition.

FIG. 2 a is an illustration of an occlusion/flush dispersion device ofFIG. 1 shown in the inflated/occlusion condition.

FIGS. 2 b through 2 f are illustrations of some alternate embodiments ofthe occlusion/flush dispersion device of the present invention.

FIG. 3 illustrates one example of an elastic skeleton usable withembodiments of the present invention, shown in the expanded state.

FIG. 4 illustrates the elastic skeleton of FIG. 3 shown in theunexpanded state.

FIG. 5 illustrates another elastic skeleton shown in the unexpandedstate.

FIG. 6 illustrates another embodiment having a sliding ring or tubesection at either end of the elastic skeleton.

FIG. 7 illustrates a cross section of a multiple lumen cannula useablewith the present invention.

FIGS. 8 a and 8 b illustrate a flap allowing rapid deployment/inflationand slower deflation of an occlusion device in accordance with anembodiment of the present invention.

FIGS. 9 a and 9 b illustrate the flap of FIGS. 8 a and 8 b asunobstructing flow during inflation of an occlusion device.

FIGS. 10 a and 10 b illustrate a flap implementation similar to that ofFIGS. 8 a and 8 b, though having a small hole therein to restrict ratherthan prevent flow back into the catheter.

FIGS. 11 a and 11 b illustrate a flap implementation similar to that ofFIGS. 8 a and 8 b, though with the flap only partially covering a holein the catheter to restrict rather than prevent flow back into thecatheter.

FIGS. 12 a and 12 b illustrate a flap implementation similar to that ofFIGS. 8 a and 8 b, though with an additional hole in the catheter torestrict rather than prevent flow back into the catheter.

FIG. 13 illustrates an embodiment of the occlusion/flush dispersiondevice of the present invention having preset folds in the covering ofthe device.

FIGS. 14 a through 14 c illustrate an embodiment of the occlusion/flushdispersion device of the present invention having an elastomeric valvewithin the catheter of the device.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Embodiments of the present invention comprise automatic occlusion/flushdispersion devices. In these devices, the occlusion/flush dispersiondevice deploys to occlude or partially occlude the artery (or vein)during the injection of the flushing solution. In fact, the flow orpressure of the flush injection is used to deploy (expand) theocclusion/flush dispersion device. Thus, during the flushing (orinfusion), the vessel is at least partially occluded at the device site,so the flush will flow preferentially distal or proximal (depending uponthe flush's exit position relative to the occlusion) into the arterial(or venous) tree and clear or dilute the path for the light orultrasound, allowing one to more effectively introduce an agent (e.g.saline solution, angiographic contrast, ultrasonic contrast) into theregion of interest or more effectively expose a therapeutic agent to avascular region of interest, to tissues adjacent to a vascular region ofinterest or tissues in the direction of the flush flow. Less flush willbe required because the vessel flow rate will be reduced by theocclusion/partial occlusion. Once the injection ceases, theocclusion/flushing device will collapse due to the lack of flushflow/pressure and vessel blood flow will resume as before the flushinjection. Because the flush lumen and the occlusion device operatinglumen can be the same lumen, the catheter can be made smaller thanconventional occlusion balloons that inflate their balloon(s) via aninflation lumen and deliver the flush via a separate flush lumen. Insome embodiments, the flush lumen may also be used as a guidewire lumento further decrease the required catheter size. Smaller catheters can bepositioned more distally (into smaller/more distal vessels) and requiresmaller introducers, resulting in lower insertion site (introducer)complications. Since the device automatically deploys during flushingand collapses at the end of flushing, there is less occlusion/flushingtime required compared to balloon occlusion systems with relatively longinflation/deflation times and/or systems with separately operatedflushing and occlusion lumens. Because the device can be configured towidely disperse the flush, the flush velocity is low, reducing thechance of vessel damage. Because the device disrupts blood flow anddisperses the flush around the catheter, there is better mixing of theflush and blood and/or better replacement of the blood by the flush andthus, less chance of protected blood streamlines or eddies.

An example of such an embodiment may be seen in FIGS. 1 and 2 a, whichshow the distal end of a representative automatic occlusion/flushdispersion device assembly that has been sliced through longitudinallyto show its contents in cross-section. The main catheter shaft 30 hasits inner diameter 32 decreased at transition section 34. Preferably, inthis transition section 34, proximal to it or in its vicinity, there areholes 36 cut in the shaft wall. Normally the occlusion/flush dispersiondevice 38 is in the retracted condition shown in FIG. 1. However whenflush is injected into the inner diameter 32 at the proximal end of thecatheter shaft 30, the change in inner diameter 32 causes an increase inflush flow resistance (a flow restriction), creating a higher flushpressure to holes 36 for the same flush flow rate than if there was noinner diameter decrease. This higher pressure is used to deploy theocclusion/flush dispersion device 38 as shown in FIG. 2 a when flush isflowing at a sufficiently high rate or pressure. In general, such flowrestriction, however created, is configured to restrict the flow throughthe catheter from the holes 36 to the distal end more than the flow isrestricted between the proximal end of the catheter and the holes 36,i.e., cause a greater pressure drop.

Also shown is a center member 40, which is used in some embodiments tofurther increase the flush pressure. This center member may be aguidewire, used also for normal distal access and vessel sub-selectionfunctions. In other embodiments, the center member 40 may not be aguidewire, but may be the optical fiber 40 or IVUS core 40. In otherembodiments, the center member 40 may be a moveable and/or removablemember 40 that may include a lumen(s) or other catheter-like features.In other embodiments, the center member 40 may include an OD increasedistal to holes 36 to provide a flow resistance increase due to therestriction of the flow space between the center member 40 and the innerdiameter 32. In other embodiments, an OD increase on the center membermay replace the functions of the transition section 34 and thus, thechange in the inner diameter 32 may be omitted. This is shown in theembodiment of FIG. 2 b. In still other embodiments, a local restrictionmay be placed inside the catheter 30, as shown in FIG. 2 c, or thecatheter shaft itself may be necked down locally to form therestriction, as shown in FIG. 2 d. The occlusion/flush dispersion device38 is, in effect, expanded or deployed by the flowing flush as it isforced out of the holes 36 and into the occlusion device 38. In oneembodiment, a material similar to that used in the embolic filtershereinbefore referred to covers the device 38, except that it covers theentire device 38 and only has holes in its distal portion 42. Theproximal portion 44 is without holes and thus forms a barrier toproximal flush flow or blood flow in the artery (or vein). The injectedflush that flows through holes 36 inflates the occlusion/flushdispersion device 38 and flows distally out of the holes in the distalportion 42, the holes in the distal portion 42 providing a restrictionfor a suitable flow rate with an associated increase in pressure in theocclusion/flush dispersion device 38 for inflation. In some embodiments,there is another flush distal flow path(s) out of the occlusion/flushdispersion device, such as if the distal end of the device 38 wheremounted on a sliding ring or tube section, as shall be described withrespect to the embodiment of FIG. 5. In some embodiments, there is asignificant flow path out of the distal end of the inner diameter 32. Inanother embodiment, the proximal portion 44 is provided with holes andthe distal portion 42 is without holes, such that the distal portion 42forms a barrier to distal flush flow or blood flow in the artery (orvein). Such an embodiment is shown in FIG. 2 e. In another embodiment,there are no holes in the distal portion 42 and the proximal portion 44,such that the device operates as purely an occlusive device and reliessolely on flow paths other than these holes for the device to collapseafter the flush. Such an embodiment is shown on FIG. 2 f.

When the flush injection is completed (no or low flush flow), theocclusion device 38 collapses as shown in FIG. 1. It collapses becausethe material (42,44) that covers the occlusion device 38 is attached toan elastic skeleton whose undeformed shape is to hug or be very close tothe outer diameter of the catheter shaft 30 inside of occlusion device38. The attachment points or areas of the cover material (42, 44) to theskeleton may be fixed attachments and/or sliding attachments. As theocclusion device 38 collapses, the flush solution in it is forced outthe holes in its distal portion 42, forced back into the inner diameter32 via holes 36 and/or forced out via other previously mentioned flushflow paths. In some embodiments, the collapse of the occlusion device 38may be assisted by the withdrawal of the device on which it is mountedproximally into the inner diameter of a sheath, catheter or guidecatheter (or via the same relative motion between the components) or byapplying a negative pressure (below atmospheric) to the inner diameter32 at the proximal end of the catheter shaft 30 for a short time.

The elastic skeleton can take on many shapes and be made of manydifferent materials with suitable elastic properties, such as NiTi andelastomeric polymers. A simple example would be a shape like used in theembolic protection devices hereinbefore referred to as shown in FIG. 3,but left in its un-expanded condition or set to an inner diametersimilar to the outside diameter of the catheter shaft 30 inside thedevice 38, as shown in FIG. 4. By way of example, a NiTi tube of theproper diameter(s) may be cut in the desired skeleton pattern, cleaned,held in a fixture and exposed to heat to set the NiTi to the desiredundeflected diameter and/or shape. Another skeleton example would be touse two or more zigzag (curved points) or sine wave-like shapes that runlongitudinally across and/or laterally around the material as shown inFIG. 5. Another skeleton example would be to use one or more zigzag(curved points) or sine wave-like shapes (either connected to each otheror not connected) that run laterally around the material and the shaft(this configuration in the connected condition is the shape ofconventional stents). Yet another skeleton example would be a shapehaving a sliding ring or tube section at either end, such as ring 52 orring 48 in FIG. 6. In some embodiments, the design of the skeleton andthe attachment method/material of the cover material may be chosen suchthat both ends of the device may be stationary relative to the shaftduring device expansion, such as the embodiment shown in FIG. 5. In someembodiments, a ring(s) may be omitted and the cover material (42,44)directly attached to the shaft. In some embodiments, the skeleton is notconnected to the shaft at its distal end and/or its proximal end. Insome skeleton embodiments, finger-like skeleton projections may also beincluded that are also attached to the cover material (42,44) to aid inthe predictability of the material's (42,44) collapse sequence and itsresulting collapsed profile. For instance, if a finger applies a greatercollapsing force to the material (42,44) than the adjacent portions ofthe skeleton, then that potion of the material (42,44) will collapsemore rapidly toward the shaft 30 than the adjacent portions. Inconjunction with preset folds in the cover material (42,44), the use ofsuch fingers can result in a substantially reduced and predictablecollapsed profile of the device. In some skeleton designs that includethe rings and/or ring and link structures/shapes of conventional stentdesigns, this controlled collapse function may also be facilitated bythe differences in the designed collapsing forces of adjacent rings.

One advantage of this invention is that the flush flow velocity to whichthe vasculature is exposed can be made much lower, because the effectiveflow cross-sectional area of the distal portion 42 can be made largerthan that of the inner diameter of the catheter shaft 30 or theeffective area of any port that may be cut into a flush lumen.Additionally, the volumetric flowrate out of any hole in distal portion42 can be much smaller than the flowrate out of the inner diameter ofthe catheter shaft 30 or the effective area of any port that may be cutinto a flush lumen. Thus, that lower flowrate flush mixes with theadjacent much lower velocity blood or other flush and slows down in amuch shorter distance than the flow out of the inner diameter of thecatheter shaft 30 or any port that may be cut into a flush lumen. Alower flow velocity reduces the chances that the flush flow stream willcause injury to the vessel wall. The flush slowing down in a shorterdistance reduces the chances that a flush flow stream with an injurioushigh flow velocity will reach the vessel wall.

Now referring specifically to FIG. 6, the material 42,44 of FIGS. 2 and6 has been cut away on the near side to expose parts of the NiTiskeleton 46. In this case, the skeleton 46 is similar to skeletons usedin the embolic protection devices hereinbefore referred to, except thatthe rest or undeflected condition of the skeleton 46 is a collapsedstate where the skeleton 46 hugs the catheter shaft 50 or is much closerto the catheter shaft 50. On its proximal end, the skeleton 46 isattached to a mounting ring 48. The mounting ring 48 is attached to thecatheter shaft 50. The distal end of the skeleton 46 is attached to thesliding ring 52. When the flush flow is low or stopped, the sliding ring52 moves distally as the occlusion device 54 collapses due to theelastic forces of the skeleton. In this embodiment, the flush may flowout of the gap between the inner diameter of the sliding ring 52 and theouter diameter of the catheter shaft 50, as well as out of the holes 66in the distal cover material 42 and holes 60 into the inner diameter 58.In another embodiment, holes 66 may be omitted and during flushing andcollapse of the occlusion device 54 the bulk of the flush flow may exitinner diameter 58 distal of the occlusion device 54. While only oneinner diameter 58 is shown in this Figure, it should be noted thatseveral lumens may be incorporated in catheter shaft 50, some of whichmay be in communication and accept at least a small portion of the flushflow. For instance the guidewire lumen and the imaging device (oroptical fiber) lumen in a multiple lumen cannula such as shown in FIG. 7may also include flush flow and holes 60 (FIG. 6). This type ofarrangement has the advantage of helping to flush air bubbles out of thecatheter lumens. Air may interfere with light or acoustic transmission.

This concept can be further expanded to include embodiments whereimaging or light transmission occurs inside the occlusion/flushdispersion device. This has an additional advantage over a balloon; airmay be trapped in a balloon, but this is very much less likely inside anocclusion/flush dispersion device. In such devices for use with light,the material covering (42,44) may be a fluorocarbon material, perhaps anexpanded fluorocarbon material, to more closely match the index ofrefraction of blood/flushing solution and aid in light transmission(limit reflection).

it is a straightforward engineering exercise to design the device andcatheter system to obtain the desired deployment (partial occlusion) orocclusion pressure (full occlusion) at the desired flush flow rate orflow rate range. The flow rate can be controlled to make such a systemsafer using a controlled pump. If the pump is connected/controlled bythe imaging system or photodynamic system controller, the deployment ofthe occlusion/flush dispersion device can be timed to further reduceflushing time. If imaging (or light application) is done inside theocclusion/flush dispersion device, the flow rate may be adjusted by theimaging system (or photodynamic system) controller to control theocclusion/flush dispersion device's deployment or occlusion pressurebased on image information (i.e. occlusion/flush dispersion deviceoutside diameter, vessel outside diameter) or other detected information(i.e. reflected light levels).

The occlusion devices of FIGS. 1, 2 and 6 may also be deployed toocclude or partially occlude a vein (e.g. Coronary Sinus, Great Cardiacvein) during the injection of a contrast solution. In fact, the flow orpressure of the contrast injection will be used to deploy the occlusiondevice. Thus, during contrast injection the vessel is at least partiallyoccluded proximal of the injection site, so the contrast will flowpreferentially distal into the venous tree and provide bettervisualization. As before, once the injection ceases, the occlusiondevice will collapse due to the lack of contrast flow/pressure andvessel blood flow will resume as before the contrast injection. Whenused for injection of a contrast solution into the coronary veins orcoronary sinus (CS), the automatic occlusion (or partial occlusion)device is preferably mounted somewhat proximal on the inner guide (butstill in the CS) or distally on the outer guide of a conventional CSaccess system. Also preferably, most of the contrast flow would be outof the distal end of the inner guide to provide a better view of thedistal coronary venous anatomy. If the device is mounted on the outerguide, contrast injected into the outer guide ID (to deploy the device)may flow into the inner guide via holes cut in the wall of the innerguide, proximally. The device would be typically used as a partialocclusion device, and if of the design of FIGS. 1, 2 and 6, theocclusion device would collapse rapidly after the contrast injection wascompleted. What is preferred is for the device to deploy (expand tosize) rapidly and then to collapse (return to a small outer diameternear the outer diameter of the guide) much more slowly. Thus, thepreferred device would inhibit CS outflow for a longer period of timeand thus, provide for a longer time that the coronary venous anatomycould be observed by fluoroscopy. While the collapse time could becontrolled by device design, there are limits as to how much differentthe deployment and collapse times can be controllably made. What isneeded is a simple way to provide a rapid deployment that requireslittle contrast flow out of the device and at the same time provides amore easily controlled and longer device collapse/retraction time. Thismay be achieved by providing a small flap(s) 62 (FIGS. 8 a and 8 b) onthe catheter shaft 50 outer diameter that covers the shaft hole(s) suchas holes 60 in FIG. 6 that feed contrast into the device to deploy(expand) it. Thus, during contrast injection (and whenever the pressurein the catheter shaft inner diameter exceeds the pressure inside thedevice by a small amount), the flap(s) 62 would be pushed away from thehole(s) (FIGS. 9 a and 9 b), allowing rapid contrast flow into thedevice to rapidly deploy the occlusion device and keep it deployed. Oncecontrast injection is stopped, the small flap(s) 62 will cover thehole(s) 60 (FIGS. 8 a and 8 b) and not allow an appreciable amount ofcontrast flow back into the shaft inside diameter from inside thedevice. The collapse time of the device is substantially controlled bythe collapsing forces of the skeleton 46 (the greater thepressure/elastic force of the skeleton 46 applied to the material (42,44), the faster the collapse) and the flow resistance of the contrastout of the device (the greater the flow resistance, the longer thecollapse time). The flap(s) 62 considerably increases the flowresistance of the contrast out of the inflated device, so the collapsetime of the device will be considerably increased. Since the flap(s) 62are pushed away from the holes 60 in the outer diameter of the shaft 50during device deployment, there is little effect on its deployment time.The collapse time may be adjusted by adjusting the skeleton 46collapsing forces (pressure), the size and number of the holes 66 in thecover (flow resistance, less holes=greater flow resistance, smallerholes=greater flow resistance), if any, and the flow resistance of thegap between the sliding ring 52 (FIG. 6) and the shaft outer diameter(if a sliding ring 52 is used). The greatest flow resistance and longestcollapse time will be when there are no holes in the cover (42, 44).With little, less or no flow of contrast out of the cover (42, 44) orout of the gap (if used) during a contrast injection, the bulk of thecontrast will flow down the inner diameter of the inner guide and outits distal end during contrast injection, as desired.

In some designs, it may be advantageous to place a small hole(s) 56 inthe flap(s) as in FIGS. 10 a and 10 b (or have the flap(s) incompletelycover the hole(s) in the outer diameter of the shaft as in FIGS. 11 aand 11 b as a failsafe or as another contrast flow path (another methodto lower or control the flow resistance of contrast flow out of thedevice). Thus, if the other flow path(s) out of the inside of the device54 becomes blocked with debris or thrombus, the device 54 will still beable to collapse or be able to be collapsed by the inner diameter of theouter guide when it is pulled back inside the outer guide. Additionallyor alternatively, if there are several holes in the shaft, one or moreholes 60 may not be provided with a flap to act as a failsafe, asillustrated by the inclusion of uncovered hole 70 in FIGS. 12 a and 12b.

Because the flap(s) 62 will be inside the device 54, it (they) will beprotected by the device 54 from contact with the vessel, outer guideinner diameter and other anatomy or devices. When blocking flow theywill also be curved about one axis, resisting deflection about anotheraxis. Thus, the flaps can be made of very thin materials (i.e.thermoplastics, elastomers, etc.), as they need not be very robust tomaintain their structural integrity. Therefore, the addition of theflaps 62 need not appreciably increase the outer diameter of the innerguide, outer guide or device.

A simple construction method would be to cut the flap(s) out of a thinsection of guide jacket material tubing and fuse a portion 64 of theflap(s) near the hole(s) 60 on the shaft outer diameter to the guidejacket or shaft 50 to attach it in place. Laser bonding the flap(s) 62to the jacket to create the fused portion(s) is an ideal method.Alternatively, hot air fusing may be used. A thin piece of anon-miscible/higher melt temperature material, like a PTFE or FEP tubesection, can be used to hold the flap 62 in place and provide the fusingforce. A heat shield and/or heat sink over the portion of flap(s) 62that must be free to move can be used to prevent it from fusing with theguide's jacket or distorting. Naturally, any attachment means may beemployed to attach or hold the flap(s) 62 in position over the hole(s)60 in the outer diameter of the shaft.

Referring again to FIG. 6, the material (42,44) has been cut away on thenear side to expose parts of the NiTi skeleton 46. The distal material42 may be provided with holes 66 to allow flush flow (the flush may becontrast (an image enhancing agent), a contrast solution, a therapeuticsolution, an energy transmission enhancing solution and/or any otherfluid solution) out of the device 54 to aid in its collapse (return toits undeployed condition) or provide diffusion of the flush distal ofthe device 54. In embodiments where flow out of the device 54 is desiredto be minimized, few holes 66 may be located in either the distal 42 orproximal 44 material, or holes 66 may be omitted from the material(42,44) entirely. Holes 60 provide for flush flow into and out of thedevice 54 via the inner diameter 58 of shaft 50. The inner diameter 58of shaft 50 may have a reduced inner diameter portion 68 that increasesthe flush flow resistance and thus increases contrast pressure duringflush flow to provide the pressure required to rapidly deploy device 54.In another embodiment, the inner diameter and outer diameter of theshaft 50 may be reduced in the area of device 54 to provide theincreased contrast pressure and/or to keep the OD of device 54 in itsundeployed state close to or smaller than the outer diameter of theshaft 50. In this embodiment, the rest condition (undeployed state) ofthe skeleton 46 is a collapsed state where the skeleton 46 hugs theshaft 50 or is very close to the shaft 50. When the flush flow is highenough, the sliding ring 52 moves proximally as the occlusion device 54deploys (expands). When the flush flow is low or stopped, the slidingring 52 moves distally as the occlusion device 54 collapses. In thisembodiment, the flush may flow out of the device 54 during its collapsevia the gap between the inner diameter of the sliding ring 52 and theouter diameter of the shaft 50, as well as out of the holes 66 in thedistal (and/or proximal) cover material 42,44 and the holes 60 via theinner diameter 58 of shaft 50.

The various embodiments of the present invention disclosed herein use anexpandable skeleton, which skeleton may be made in many ways. Oneparticular method of making the skeleton already mentioned herein is tocut a thin-walled tubular member, such as nickel-titanium hypotube, toremove portions of the tubing in the desired pattern for each strut orfinger, leaving relatively untouched the portions of the tubing whichare to form each strut. The tubing may be cut into the desired patternby means of a machine-controlled laser. In the case of devices disclosedherein that have a collapsed free state, as in the embodiments such asthat of FIGS. 1, 2 and 6, the patterned tubing could be held in the ascut condition/pattern when heated to set its shape, or even deformedradially inward a bit to provide a preload toward the collapsedcondition when in use to effectuate the complete collapse desired.

The tubing used to make the skeleton could be made of other suitablebiocompatible metallic materials such as spring steel. Elgiloy isanother material that could possibly be used to manufacture theskeleton. Also, polymers could be cut or formed using conventionalpolymer possessing, cutting and/or forming techniques to manufacture theskeleton, provided they are sufficiently flexible and bendable.

The polymeric material which can be utilized to create the covering forthe devices of the disclosed embodiments of the present inventioninclude, but are not limited to, polyurethane, polyester and Gortex, acommercially available expanded fluorocarbon material. Other possiblesuitable materials include ePTFE. The material can be elastic ornon-elastic, woven or non-woven. In that regard, elastic as used hereinmeans stretchable, whereas non-elastic means relatively non-stretchable,though in either event, the material must be readily foldable withoutcracking or other failure, and in some embodiments, have a memory so asto have a bias tending to cause the material to return to the foldedstate unless forceably held in an inflated state. The wall thickness ofthe covering can be about 0.00050-0.0050 inches. The wall thickness mayvary depending on the particular material selected. The material can bemade into a cone or similarly sized shape utilizing for example,blow-mold technology or dip technology. The holes can be any differentshape or size. A laser, a heated rod or other process can be utilized tocreate the holes in the covering material or the holes may be aconsequence of the weave or expansion of the material. The holes would,of course, be properly sized and numbered to provide the desired flowrates and restrictions. The holes could be lazed in a spiral pattern orsome similar pattern that will aid in the re-wrapping or folding of themedia during closure of the device. The end result is a porous coveringportion, whether created by holes in that portion of the cover, by theweave forming that portion of the cover or by some other characteristicsof that portion of the cover or its preparation. Additionally, thematerial can have a “set” put in it much like the “set” used indilatation balloons to make the material rewrap or fold more easily andpredictably when transitioning to the collapsed condition. Such anembodiment is shown in FIG. 13. As shown therein, in this embodiment,the flexible cover wraps around the catheter shaft as it collapses. Insuch an embodiment, the skeleton may be cut and set with ribs similarlyshaped and hugging the catheter shaft, so that the skeleton can expandin a manner similar to the cover, and help encourage folding as setduring deflation.

Now referring to FIGS. 14 a through 14 c, a further alternate embodimentmay be seen. In this embodiment, instead of using a step-down in theinner diameter of the catheter to concentrate the pressure drop in thecatheter at the openings to the inflatable occlusion/flush dispersiondevice 38, an elastomeric valve may be used, such as in an otherwiseconstant inner diameter catheter. Thus as shown in FIG. 14 a, anelastomeric valve 70 is shown blocking or at least substantiallyblocking the distal end of the catheter 50 within vessel 74. The valveis supported by a wire 72, in turn supported either from the proximalend of the catheter or from a substantially non-obstructing supportwithin the catheter. Such a valve will deflect slightly, like adiaphragm, when subjected to low pressures, as shown in FIG. 14 b,allowing the flow to go exclusively or primarily to inflate theocclusion/flush dispersion device 38 shown schematically, but when theocclusion/flush dispersion device 38 is inflated to occlude the artery(or vein), an increase in pressure such as resulting from no furtherinflation of the occlusion/flush dispersion device 38 will cause thevalve 70 to collapse, as shown schematically in FIG. 14 c. In thatregard, the initial diaphragm-like deflection of the elastomeric valvecauses circular compression stresses in the elastomeric material, thoughthe valve will remain as a surface or volume of revolution. At somelarger pressure, the circular compression stresses will cause the valveshape to become unstable, forming pleats in the elastomeric valve likein a coffee filter, allowing it to collapse further with little increasein pressure. Thus such an elastomeric valve can serve a safety function,assuring the occlusion/flush dispersion device 38 will properly inflateat some minimum flow rate or pressure, but will prevent over pressuringthe occlusion/flush dispersion device 38 if the flow rate or pressure istoo high, even momentarily. The elastomeric valve can thus act as apressure regulator, reducing the flow rate/pressure control requirementsduring use of the system.

Thus while certain preferred embodiments of the present inventioncatheter mounted automatic vessel occlusion and flush dispersion deviceshave been disclosed and described herein for purposes of illustrationand not for purposes of limitation, it will be understood by thoseskilled in the art that various changes in form and detail may be madetherein without departing from the spirit and scope of the invention.

What is claimed is:
 1. A catheter mounted automatic vessel occlusion andflush dispersion device comprising: a catheter shaft having an innerdiameter, an outer diameter, and a wall therebetween, an open proximaland distal end, and a flow restriction between the proximal end and thedistal end, wherein the flow restriction includes an elastomeric valvein the catheter shaft, the elastomeric valve obstructing flow throughthe distal end of the catheter shaft at low fluid pressures on theelastomeric valve, and deflecting at higher fluid pressures to presentreduced flow obstruction, and wherein the elastomeric valve comprises acircular elastomeric member supported concentrically with respect to theinner diameter of the catheter shaft by a support coupled to a center ofthe circular elastomeric member; an expandable skeleton over thecatheter shaft adjacent the distal end, the expandable skeleton having afirst and second end and an elastically deflectable portion between thefirst and second end, the elastically deflectable portion beingelastically deflectable in a radially outward direction; a flexiblecovering to occlude a blood vessel when inflated, the flexible coveringattached to the expandable skeleton at attachment points on theelastically deflectable portion; and, at least one opening through thewall and proximal to the flow restriction to inflate the flexiblecovering when a fluid flow is provided in the catheter shaft.
 2. Thedevice of claim 1 wherein a proximal end of the flexible covering is notporous and a distal end of the flexible covering is porous forcontrolled flow of fluid out of the distal end of the flexible coveringwhen the flexible covering is inflated by the fluid flow in the cathetershaft.
 3. The device of claim 1 wherein a distal end of the flexiblecovering is not porous and a proximal end of the flexible covering isporous for controlled flow of fluid out of the proximal end of theflexible covering when the flexible covering is inflated by the fluidflow in the catheter shaft.
 4. The device of claim 1 wherein the flowrestriction restricts, but does not block, the fluid flow through thecatheter shaft from the at least one opening to the distal end of thecatheter shaft more than the fluid flow is restricted between theproximal end of the catheter shaft to the at least one opening.
 5. Thedevice of claim 4 wherein the flow restriction includes a reduction inthe inner diameter of the catheter shaft.
 6. The device of claim 4further comprising an elongate object within the catheter shaft tocreate the flow restriction, the elongate object having an increasedouter diameter between the at least one opening and the distal end ofthe catheter shaft.
 7. The device of claim 6 wherein the elongate objectincludes a guidewire extending through the catheter shaft.
 8. The deviceof claim 6 wherein the elongate object includes an optical fiberextending through the catheter shaft.
 9. The device of claim 6 whereinthe elongate object includes an intravascular ultrasound core extendingthrough the catheter shaft.
 10. The device of claim 1 wherein theexpandable skeleton is set in a collapsed state so that the expandableskeleton hugs the outer diameter of the catheter shaft when the flexiblecovering is not inflated.
 11. The device of claim 1 wherein the at leastone opening is at least partially covered with a flexible flap attachedto the outer diameter of the catheter shaft to unobstruct the flow offluid through the at least one opening from the inner diameter of thecatheter shaft to inflate the flexible covering and to at leastpartially obstruct flow of fluid back into the catheter shaft when theflexible covering is deflated.
 12. The device of claim 11 wherein theflexible flap comprises a hole, the hole being smaller than the at leastone opening.
 13. The device of claim 11 wherein the at least one openingis a plurality of openings, all the openings being at least partiallycovered with flexible flaps.
 14. The device of claim 1 wherein theflexible covering comprises an elastic flexible covering.
 15. The deviceof claim 1 wherein the flexible covering comprises an inelastic flexiblecovering.
 16. The device of claim 1 wherein the catheter shaft comprisesa multiple lumen catheter shaft.
 17. The device of claim 1 wherein afirst and second end of the flexible covering are each fixed withrespect to the catheter shaft.
 18. The device of claim 1 wherein a firstend of the flexible covering is fixed with respect to the catheter shaftand a second end of the flexible covering is coupled to a ring adaptedto slide with respect to the catheter shaft.